Device for welding metal foils and the like



Feb. 18, 1964 -r. J. SCARPA ETAL DEVICE FOR WELDING METAL FOILS AND THE LIKE 2 Sheets-Sheet 1 Original Filed May 26, 1958 Mid mokmmmzww o o mfii Q Q T H F 3 mm M U M? u N a /w P T 3 N T 5 0 RN ME 0C HmY Tv QM l v 1964 T. J. SCARPA EI'AL 13,121,353

DEVICE FOR WELDING METAL FOILS AND THE LIKE Original Filed May 26, 1958 2 Sheets-Sheet 2 Ys 53 w & 0

0 "WW (77W m E N g V Ill" ill Hu -.w wv --"|l| l|w I A A AvA A A e Eg- INVENTORS THOMAS J. SCQRPFI VINCENT P FFIRLEY FFTTOE/VEY {a circuit of V3V4 and is used as a. tuning indicator .when adjusting inductors 23 and 26.

By way of illustration and not by way of limitation of the scope of our invention, following is an example of an ultrasonic welding device of our invention:

Operating frequency-2Q kc.

Transducer 13, formed largely of barium titanate, lcngth3%, outside diameter1 /z", inside diametcr1 /s Mechanical transformer 1.4, formed of stainless steel, diameter of base of conical portion i52.25 height of conical portion l5-l.94", diameter of bases of cylinder l6l.0=70", height of cylinder l-O.25Q height of conical portion i18-2.75", diameter of shank l90.375, length of blade 2i)1.l25, thickness of blade 0.125".

Length of housing 12-7, outside diameter of housing 122.5(), thickness of housing wali- Thickness of nodal flange 170.250.

Under the conditions set forth in the example set forth just above, we have been able to weld metal foils of thickness of the order of 0.004 inch using the following method:

The metal foils to be welded are placed so that they overlap in the region wherein it is desired to form the weld and ultrasonic excitation is applied to the welder. Then, the tool is placed in contact with the foils and is moved along the desired seam. We have found that it is possible and practical to hold the foils to be welded in fixed positions and to move the Welder along the seam. In such cases, the Welder may be held in the hand or in a movable mechanical cradle and moved either by hand or by mechanical means. On the other hand, the welders of our invention may also be held in a fixed position and arranged so that the metal foils are moved with respect to the tool either by hand or by mechanical means.

We have found that foil welding may be accomplishe using the teachings of our invention within the frequency range of 15 kc. to kc. but that the range of 18 kc. to 22 kc. is preferred.

It is also within the contemplation of our invention to utilize the ultrasonic device of Richard D. McGunigle where higher powers are required in order to weld thicker sheets of foil or when it is desirable to weld several thin sheets together. The device of Richard D. McGunigle has been described in his application for Letters Patent entitled Ultrasonic Device, Serial No. 731,744 and assigned to the :assignee hereof.

It is possible by using the method of our invention to hermetically seal foods and other materials which are to be preserved for long periods of time in a control-led, sealed environment. In fact, it is within the contemplation of our invention to treat foods and other materials specially, by radiation, dehydration or other processes, and to seal the contents in aluminum or other thin noncontarninating metal foil immediately after treatment. This will prevent the contents from being exposed to any deleterious atmospheric conditions for too long a time. This technique is possible because no heat is used in carrying out our method of welding foils by ultrasonic means.

We have also welded all but a small portion of a seam and then removed most of the air from the inside and finished the seam. By this technique, one is able to achieve vacuum packing of materials in thin metal bags whereas previously vacuum packing has only been available in glass jars and relatively rigid metal cans.

While we have disclosed our invention in relation to specific examples and in specific embodiments, we do not wish to be limited thereto, for obvious modifications will occur to those skilled in the ant without departing from the spirit and scope of our invention.

Having thus described our invention, we claim:

1. In a sonic welder comprising a sonic generator, a member mounted for vibrational movement along a given axis, means res onsive to said sonic generator for vibrating said member along said axis at a sonic frequency, the

improvement comprising: a welding tool aifixed to the end of said member to be vibrated longitudinally along said axis, said tool comprising a longitudinally extending shank portion connected to said member and a thin blade extending laterally from the end of said shank portion, the plane of said blade extending generally parallel to said axis, the end of said blade constituting the Work contacting portion of the tool and being vibrated by said member in a transverse mode where the blade end vibrates in a direction having a substantial component parallel to the plane of the blade.

2. The welder of claim 1 wherein said blade has a length equal to an integral multiple of half wave lengths at the frequency of vibration thereof.

3. The welder of claim 1 wherein said blade makes an angle of with respect to said shank portion of the tool.

4. The sonic welder of claim 1 wherein said blade makes an obtuse angle with respect to the shank portion of said tool not exceeding References Cited in the file of this patent UNITED STATES PATENTS 2,947,886 McGunigle Aug. 2, 1960 2,990,616 Balamuth luly 4, 1961 FOREIGN PATENTS 1,087,440 France Aug. 25, 1954 

1. IN A SONIC WELDER COMPRISING A SONIC GENERATOR, A MEMBER MOUNTED FOR VIBRATIONAL MOVEMENT ALONG A GIVEN AXIS, MEANS RESPONSIVE TO SAID SONIC GENERATOR FOR VIBRATING SAID MEMBER ALONG SAID AXIS AT A SONIC FREQUENCY, THE IMPROVEMENT COMPRISING: A WELDING TOOL AFFIXED TO THE END OF SAID MEMBER TO BE VIBRATED LONGITUDINALLY ALONG SAID AXIS, SAID TOOL COMPRISING A LONGITUDINALLY EXTENDING SHANK PORTION CONNECTED TO SAID MEMBER AND A THIN BLADE EXTENDING LATERALLY FROM THE END OF SAID SHANK PORTION, THE PLANE OF SAID BLADE EXTENDING GENERALLY PARALLEL TO SAID AXIS, THE END OF SAID BLADE CONSTITUTING THE WORK CONTACTING PORTION OF THE TOOL BEING VIBRATED BY SAID 